I agree with Pat, for us it is the expense first. I use
this method for bulk buying. I take a copy of a grocery list:
http://www.donnayoung.org/household/fullsize/ffiles/kifiles/grocery.pdf
Then
I note what we have on hand. On an exact copy I note what we will
use for one month, then I multiply by 13. This gives me a pretty
good idea of what I use in a year and what I have on hand.
I know
from experience that we will eat 2 bone in hams and 2 boneless hams a
year, so I wait until Christmas or Easter and stock up. We
eat about 28 pounds of pork a year, so I stock up in the spring and
fall at slaughter time, and only buy the cuts we eat, and so on.
I always buy bulk spices and herbs
We buy almost all our starches, rice, pasta, instant potatoes, grains in bulk.
We
love tuna and salmon canned, so we buy 48 cans of each when we hit a
good sale. Other fishes, such as clams, smoked oysters, canned crab we
buy as we come across a good deal.
We do the same for each room
in the house, inventorying everything in that room. I know when I need
new linens, new socks, toothbrushes, etc., just by checking my
inventory. And it helps me keep things purged. : )